Apparatus for guiding sheet

ABSTRACT

An apparatus for guiding magnetisable metal sheet or strip in a processing line. A set of rollers are mounted with their longitudinal axes inclined at a small angle to the normal to the direction of movement of the sheet so that sheet contacting the rollers will be given a lateral component of movement in one sense. The stator parts of a series of linear induction motors are mounted between the rollers so that when energised they apply a lateral force to the sheet in the same sense. In operation the sheet is also attracted towards the stator parts of the linear induction motors and hence towards the rollers, and the angled rollers are thereby utilised to assist the electromagnetic steering force on the sheet.

Sandman [451 Sept. 25, 1973 l l APPARATUS FOR GUlDlNG SHEET KeithHamilton Sandman, Horsell, Woking, Surrey, England [73] Assignee: TheBritish Iron and Steel Research Association, London, England [75]Inventor:

[22] Filed: Dec. 4, 1972 [2U Appl. No.: 311,557

[30] Foreign Application Priority Data Dec. 3, 1971 Great Britain56,287/71 [52] US. Cl 226/15, 226/93, 27l/63 A [51] Int. Cl B65h 17/18[58] Field of Search 226/93, 94, 3, 15;

[56] 7 References Cited UNITED STATES PATENTS 2,228,913 l/l94l Martin27l/63 A 2,750,l87 6/1956 Bannister 226/93 X Primary Examiner-Richard A.Schacher Attorney-Leo A. Rosetta et a].

[ 57] ABSTRACT An apparatus for guiding magnetisable metal sheet orstrip in a processing line. A set of rollers are mounted with theirlongitudinal axes inclined at a small angle to the normal to thedirection of movement of the sheet so that sheet contacting the rollerswill be given a lateralcomponent of movement in one sense. The statorparts of a series of linear induction motors are mounted between therollers so that when energised they apply a lateral force to the sheetin the same sense. In operation the sheet is also attracted towards thestator parts of the linear induction motors and hence towards therollers, and the angled rollers are thereby utilised to assist theelectromagnetic steering force on the sheet.

10 Claims, 7 Drawing Figures PATENTEI] SEP2 5 I975 SHEET 1 [IF 3 saw 2BF APPARATUS FOR GUIDING SHEET Guiding and steering metal sheet duringits produc- 9 tion in process lines and mills is at present done by oneof three methods. The simplest method is by side guides, either staticor moving, which bear against both edges of the sheet and so keep it oncourse. The second method is to use self-centering rolls, i.e., rollswith convex-contoured bodies which effect lateral correction by creatingtensile distortions in the strip. Thus with a crowned roll, if the sheetdeviates from the central position, the crown creates a lateral tensiledistortion in the strip resulting in it becoming cambered such that thematerialis returned towards the centre of the roll in aligning itselfperpendicular to the roll axis. The third method involves movable rolls.

There are problems associated with all these known methods and an objectof this invention is to provide a simple means of guiding magnetisablemetal sheet.

According to the present invention there is provided apparatus forguiding elongate sheet of magnetisable metal in a predetermineddirection of movement including a first series of rollers along whichsheet is advanceable in said predetermined direction, the longitudinalaxes of the rollers being inclined to the normal to said direction sothat sheet contacting said first series of rollers will be given alateral component of movelatter arrangement the plane tangent to therollers of the first series is preferably slightly inclined to the plane7 tangent to the rollers of the second series so that when ment in afirst sense, and a linear induction motor primary member disposedrelative to said rollers so that when the primary member is energised, alateral force is said first sense is applied to the sheet being advancedand the sheet is attracted to contact rollers of the first series.

Linear induction motors are known for providing linear electromagneticforces. The induction motor consists of a primary member carryingwindings to be energised with polyphase electric current, and asecondary member which can simply be a sheet of metal. One of theproblems usually associated with linear induction motors is that theattractive force between the primary member and a secondarymember ofmagnetisable material is greater than the electromagnetic forces tendingto cause the sheet to move across the face of the primary member. Bycontrast the present invention uses the attractive force to supplementthe lateral electromagnetic forces on the sheet.

It is possible for the sheet to be prevented from moving laterally inthe opposite sense to said first sense by a fixed guide. Preferably,however, the apparatus includes a second series of rollers along whichsheet is advanceable in said direction, the axes of the rollers of thesecond series being slightly inclined to the axes of the rollers of thefirst series so that sheet contacting said second series of rollers willbe given a lateral component of movement'in the opposite sense to saidfirst sense, and a second linear induction motor primary. memberdisposed so that when it is energised a lateral force in saidoppositesense is applied to the sheet being advanced and the sheet isattracted to contact rollers of said second series.

In one possible arrangement the first and second'series of rollers arespaced so that in use the sheet passes between them. The spacing betweenthe first and second series may be adjustable to accommodate sheet ofdifierent thicknesses. In another possible arrangement the first andsecond series of rollers are disposed side by side to contact the samesurface of the sheet. In the a sheet is attracted into contact with oneseries of rollers it is out of contact with the other series of rollers.The apparatus preferably includes a sensor to sense the lateral positionof a sheet, and control means to control the primary members in responseto a signal from the sensor. There could be sensors at each edge of thesheet in order to sense the position of the centre of the sheet.

In the accompanying drawings:

FIG. 1 shows a side view of one apparatus according to the invention inuse on a horizontal sheet storage loop,

FIG. 2 is a plan view, partly cut away, of a part of the apparatus ofFIG. 1,

FIG. 3-shows a plan view of a second apparatus according to theinvention,

FIG. 4 is a side view of the apparatus of FIG. 3.

' FIG. 5 shows a plan view of a third apparatus according to theinvention, and

FIGS. 6 and 7 are side and end views respectively of the apparatus ofFIG. 5.

In many processes where sheet steel is handled a storage loop defining apath along which sheet is advanced is provided to enable the process tocontinue while the beginning of a new coil is welded to the end of thesheet already being processed. The apparatus of the storage loop forsheet steel 2 shown in FIG. 1 includes a first and second roll 4 and 6and a roll 8 mounted on a wheeled carriage 10 which is biased by aspring 12 so as to take up any slack in the sheet 2. The sheet is guidedlaterally by guiding apparatus mounted on a wheeled carriage 14connected by a link 16 to the carriage 10. It is to be understood thatguiding apparatus could be mounted on an enlarged carriage 10 instead ofhaving a separate carriage 14.

The guiding apparatus includes a first series of rollers 18, a secondseries of rollers 20, a number of linear induction motor primary members22 arranged to cooperate with the rollers 18 and a second set of primarymembers 24 arranged to cooperate with the rollers 20. The rollers 18 aremounted in bearings 26 and the rollers 20 in bearings 28 connected tothe carriage 14 so that the sheet 2 passes between the two series ofrollers. The axes of the rollers 18 are slightly inclined to the axes ofthe rollers 20 so that if the sheet 2 is in contact with the rollers 18it will be given a lateral component of movement in one sense as it isadvanced in the direction of the arrow p and if the sheet 2' is incontact with the rollers 20 it will be given a lateral component ofmovement in the opposite sense. Each series of rollers isinclined at anangle of less than three degrees'to the normalfto the direction ofmovement P" of the sheet There is a primary member 22, 24 parallel toand between adjacent pairs of rollers 18, 20 in each series of rollers.The primary members 22 are wound so that when energised a lateral forceis applied to the sheet 2 in the same sense as the force is applied bythe inclination of the rollers 18. The primary members 24 are wound toapply a lateral force to the sheet 2 in the opposite sense.

A sensor 30 is disposed adjacent to one edge of the sheet 2 to sense itsposition. A signal from the sensor 30 is fed to a comparator 32 whichcompares the signal with a signal 34 indicating the desired sheetposition. A signal is then fed from the comparator 32 to a variablevoltage or variable power controller 36 which controls the supply to theprimary members 22, 24.

When the sensor 30 senses that the sheet 2 hasdeviated laterally fromits desired position, for example upwardly in FIG. 2, the controller 36energises the primary members 22 which apply a lateral force to thesheet 2 tending to deflect the sheet back towards its desired position.Simultaneously the primary members 22 atrract the sheet 2 into contactwith the series of rollers 18 which therefore also deflect the sheet 2in the same sense. The primary members 24 can remain unenergised oralternatively they can be energised with the windings reversed'so as toprovide a lateral force to supplement that of the primary members 22.

If the windings 24 are energised they must either be supplied with lesspower than the primary member 22 so that the sheet 2 is attracted morestrongly to the rollers 18, or they can be energised slightly after theprimary members 22 so that the strip once attracted to the rollers 18would remain in contact with them.

In the arrangement shown in FIGS. 3 and 4 a first and second series ofrollers 50, 52 are spaced so that the sheet 2 passes between them as inFIG. 2. The arrangement differs from FIG. 2 in that the rollers 50 aremounted in a first frame 54 and the rollers 52 are mounted in a secondframe 56, the two frames 54 and 56 being movable relative to oneanother. The frame 54 is supported on the frame 56 by springs 58 whichurge the frame 54 away from the frame 56. A stop 60 limits upwardmovement of the frame 54. Pairs of rolls 62 are located at the front andrear ends of the frames 54, 56. The rolls 62 are mounted in housings 66pivoted at 68 to the frames 54, 56 in such a manner that the rolls 62are behind the pivots 68 and therefore the rolls 62 cannot exert amistracking force on the strip 2 moving in the direction of the arrow.

Two series of linear motor primary members 70 are disposed between therollers 50 52 as in the arrangement of FIG. 2. When either series ofprimary members 70 are energised the upper frame 54 will move towardsthe frame 56 under the attractive force of the primary members 70 andwill overcome the force in the springs 58. The rolls 62 space the frames54, 56 apart by a distance which takes account of the thickness of thestrip 2. Thus when very thin strip 2 is being processed the gap betweenthe upper and lower units is automatically reduced so as to obtainmaximum thrust from the primary members 70.

As in FIG. 2 a sensor 30, comparator 32 and controller 36 are providedfor controlling the primary members 70. In addition one of the rollers50 and one of the rollers 52 are each provided with a load cell (notshown) to indicate which set of rollers the sheet 2 is in contact with.The load cells control the power to each set of primary members 70 sothat the sheet is in contact with the appropriate set of rollers tosteer the sheet in the right direction.

In the arrangement shown in FIGS. 5 to 7 a first and second series ofrollers 40, 42 are disposed side by side to contact the under surface ofthe sheet 2. The axes of the roller 40 and 42 are slightly inclined toone another so that each series tends to deflect the sheet 2 moving inthe direction of the arrow P" towards the other series. There is alinear motor primary member 44 between each adjacent pair of rollers 40and a primary member 46 between each adjacent pair of rollers 42. Theprimary members 44, 46 are mounted on supports 48. As can be seen inFIG. 7 the plane tangent to the rollers 40 of the first series isslightly inclined to the plane tangent to the rollers 42 of the secondseries. A sensor 30, comparator 32 and controller 36 are providedsimilar to those in FIG. 2.

When the sheet 2 deviates laterally from its desired position theappropriate primary members 44 or 46 are energised. The attractive forcethat attracts the sheet into contact with one series of rollers 40 or 42lifts the sheet out of contact with the other series of rollers 42 or 40respectively as can be seen in FIG. 7. The rollers therefore apply alateral force to the sheet to supplement the lateral force of theprimary members.

In process lines where the surface finish of the sheet is important therollers can be covered with a material such as rubber or polyurethane.

The invention provides a simple guiding device for magnetisable sheetmetal by means of linear induction motors in which the attractive forceis utilised to assist the electromagnetic steering force.

We claim:

1. Apparatus for guiding elongate sheet of magnetisable metal in apredetermined direction of movement including a first series of rollersalong which sheet is advancable in said predetermined direction, thelongitudinal axes of the rollers being inclined to the normal to saiddirection so that sheet contacting said first series of rollers will begiven a lateral component of movement in a first sense, and a linearinduction motor primary member disposed relative to said rollers so thatwhen the primary member is energised, a lateral force in said firstsense is applied to the sheet being advanced and the sheet is attractedto contact the rollers of the first series.

2. Apparatus according to claim 1 including a second series of rollersalong which sheet is advancable in said direction, the axes of therollers of the second series being slightly inclined to the axes of therollers of the first series so that sheet contacting said second seriesof rollers will be given a lateral component of movement in the oppositesense to said first sense, and a second linear induction motor primarymember disposed relative to said second series of rollers so that whenthe second primary member is energised, a lateral force in said oppositesense is applied to the sheet being advanced and the sheet is attractedto contact rollers of said second series.

3. Apparatus according to claim 2 in which the first and second seriesof rollers are spaced so that in use the sheet passes between them.

4. Apparatus according to claim 3 which the spacing between the firstand second series of rollers is adjustable to accommodate sheet ofdifferent thicknesses.

5. Apparatus according to claim 2 in which the first and second seriesof rollers are disposed side by side to contact the same surface of thesheet.

6. Apparatus according to claim 5 in which the plane tangent to therollers of the first series is slightly inclined to the plane tangent tothe rollers of the second series so that when a sheet is attracted intocontact with one series of rollers it is out of contact with the otherseriesof rollers.

7. Apparatus according to claim 1 in which a number of primary membersare arranged to cooperate with the series of rollers to apply lateralforces to the sheet.

6 8. Apparatus according to claim 7 in which primary 10. Apparatusaccording to claim 1 including a senmembers are disposed betweenadjacent pairs of roll-- sor to sense the lateral position of a sheet,and control ers. means to control the primary member or members in 9.Apparatus according to claim I mounted on a response to a signal fromthe sensor means. wheeled carriage. 5

1. Apparatus for guiding elongate sheet of magnetisable metal in apredetermined direction of movement including a first series of rollersalong which sheet is advancable in said predetermined direction, thelongitudinal axes of the rollers being inclined to the normal to saiddirection so that sheet contacting said first series of rollers will begiven a lateral component of movement in a first sense, and a linearinduction motor primary member disposed relative to said rollers so thatwhen the primary member is energised, a lateral force in said firstsense is applied to the sheet being advanced and the sheet is attractedto contact the rollers of the first series.
 2. Apparatus according toclaim 1 including a second series of rollers along which sheet isadvancable in said direction, the axes of the rollers of the secondseries being slightly inclined to the axes of the rollers of the firstseries so that sheet contacting said second series of rollers will begiven a lateral component of movement in the opposite sense to saidfirst sense, and a second linear induction motor primary member disposedrelative to said second series of rollers so that when the secondprimary member is energised, a lateral force in said opposite sense isapplied to the sheet being advanced and the sheet is attracted tocontact rollers of said second series.
 3. Apparatus according to claim 2in which the first and second series of rollers are spaced so that inuse the sheet passes between them.
 4. Apparatus according to claim 3which the spacing between the first and second series of rollers isadjustable to accommodate sheet of different thicknesses.
 5. Apparatusaccording to claim 2 in which the first and second series of rollers aredisposed side by side to contact the same surface of the sheet. 6.Apparatus according to claim 5 in which the plane tangent to the rollersof the first series is slightly inclined to the plane tangent to therollers of the second series so that when a sheet is attracted intocontact with one series of rollers it is out of contact with the otherseries of rollers.
 7. Apparatus according to claim 1 in which a numberof primary members are arranged to cooperate with the series of rollersto apply lateral forces to the sheet.
 8. Apparatus according to claim 7in which primary members are disposed between adjacent pairs of rollers.9. Apparatus according to claim 1 mounted on a wheeled carriage. 10.Apparatus according to claim 1 including a sensor to sense the lateralposition of a sheet, and control means to control the primary member ormembers in response to a signal from the sensor means.